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SEO Keyword Expansion

SEO API documentation for REST and MCP, generated from the implemented API contract.

API selector
Keyword Research

API overview

Deduplicated suggestions and related keywords with source relationships. Calls are idempotent by user, slug and UUID key. Free owner-only result retrieval: GET /api/skill-api/v1/skills/seo-keyword-expand/calls/{callId} or nexscope_seo_call_result. Evidence is retained for seven days. Missing values are not zero. Examples describe structure only and are not measured results.

Try this API
Endpoint
/api/skill-api/v1/skills/seo-keyword-expand/run
MCP method
nexscope_seo_keyword_expand

Authentication

All run endpoints require a user API key. Send it as a bearer token in the Authorization header.

Authorization: Bearer nk-xxxxxxxxxxxxxxxxx
Missing or invalid API keys return an authentication error. Manage keys from .
POST/api/skill-api/v1/skills/seo-keyword-expand/run

Run an API

Send a JSON request body using the parameters described below.

Slugseo-keyword-expand
HeadersAuthorization: Bearer nk-...
Content-Type: application/json
Request bodyAPI-specific JSON object.
Response bodyComplete HTTP envelope, including code and data.

Status codes

CodeDescription
200HTTP request completed. Check JSON code; only 0 indicates business success or acceptance.
400Request JSON or required API parameters are invalid.
401API key is missing, invalid, or cannot be matched to a user.
5xxAPI execution or upstream service failed.

Example request

curl -X POST https://api.nexscope.ai/api/skill-api/v1/skills/seo-keyword-expand/run \
  -H "Authorization: Bearer nk-xxxxxxxxxxxxxxxxx" \
  -H "Content-Type: application/json" \
  -d '{   "keyword": "nexscope",   "language": "en",   "limit": 10,   "market": "US",   "sources": [     "suggestions",     "related"   ] }'
All categories/ Keyword Research
POST/api/skill-api/v1/skills/seo-keyword-expand/run

Run this API

Send a JSON request to execute this API and receive the documented response payload.

Open tester

Endpoint

MethodPOST
Path/api/skill-api/v1/skills/seo-keyword-expand/run
AuthBearer API key
Content-Typeapplication/json

Request body

NameTypeRequiredDescription
keywordstringrequired
Trimmed, at most ten whitespace-separated words.
Minimum length: 1
Maximum length: 80
languagestringrequired
Language value used by this API operation.
Allowed: en
limitintegeroptional
Limit value used by this API operation.
Default: 10
Minimum: 1
Maximum: 20
marketstringrequired
Market value used by this API operation.
Allowed: US
sourcesarrayoptional
Sources value used by this API operation.
Default: ["suggestions","related"]
Minimum items: 1
Maximum items: 2
sources[]stringrequired
Item in sources.
Allowed: suggestions, related

Request example

{
  "keyword": "nexscope",
  "language": "en",
  "limit": 10,
  "market": "US",
  "sources": [
    "suggestions",
    "related"
  ]
}

Response body

NameTypeRequiredDescription
codeintegerrequired
0 is a successful envelope; inspect data.status separately.
Allowed: 0, 42008, 42009
coststringrequired
Elapsed processing milliseconds; not price. -1 for non-web context.
dataobjectrequired
Data value used by this API operation.
data.callIdstringoptional
Call id value used by this API operation.
Format: uuid
data.completedAtstring | integer | nulloptional
UTC epoch milliseconds.
data.coverageobjectoptional
Coverage value used by this API operation.
data.coverage.missingarrayoptional
Missing value used by this API operation.
data.coverage.missing[]objectrequired
Item in data coverage missing.
data.coverage.missing[].fieldstringoptional
Field value used by this API operation.
data.coverage.missing[].reasonstringoptional
Reason value used by this API operation.
data.coverage.statusstringoptional
Status value used by this API operation.
data.reasonstringoptional
Stable reason on errors 42001 through 42011; accepted errors retain callId.
data.requestedAtstring | integer | nulloptional
UTC epoch milliseconds.
data.resultobject | nullrequired
Result value used by this API operation.
data.result.itemsarrayoptional
Items value used by this API operation.
data.result.items[]objectrequired
Item in data result items.
data.result.items[].keywordstring | nulloptional
Keyword value used by this API operation.
data.result.items[].keywordDifficultynumber | nulloptional
Keyword difficulty value used by this API operation.
data.result.items[].missingarrayoptional
Missing value used by this API operation.
data.result.items[].missing[]objectrequired
Item in data result items[] missing.
data.result.items[].missing[].fieldstring | nulloptional
Field value used by this API operation.
data.result.items[].missing[].reasonstring | nulloptional
Reason value used by this API operation.
data.result.items[].relationsarrayoptional
Relations value used by this API operation.
data.result.items[].relations[]objectrequired
Item in data result items[] relations.
data.result.items[].relations[].depthinteger | nulloptional
Depth value used by this API operation.
data.result.items[].relations[].seedstring | nulloptional
Seed value used by this API operation.
data.result.items[].relations[].sourcestring | nulloptional
Source value used by this API operation.
data.result.items[].searchVolumeinteger | nulloptional
Search volume value used by this API operation.
data.result.languagestring | nulloptional
Language value used by this API operation.
data.result.marketstring | nulloptional
Market value used by this API operation.
data.result.requestedLimitinteger | nulloptional
Requested limit value used by this API operation.
data.result.returnedCountinteger | nulloptional
Returned count value used by this API operation.
data.result.seedstring | nulloptional
Seed value used by this API operation.
data.result.sourcesarrayoptional
Sources value used by this API operation.
data.result.sources[]objectrequired
Item in data result sources.
data.result.sources[].missingReasonstring | nulloptional
Missing reason value used by this API operation.
data.result.sources[].returnedCountinteger | nulloptional
Returned count value used by this API operation.
data.result.sources[].sourcestring | nulloptional
Source value used by this API operation.
data.result.sources[].statusstring | nulloptional
Status value used by this API operation.
data.retryablebooleanoptional
Retryable value used by this API operation.
Constant: false
data.schemaVersionstringoptional
Schema version value used by this API operation.
Constant: 1.0
data.sourcestringoptional
Source value used by this API operation.
Constant: dataforseo
data.statusstringoptional
Status value used by this API operation.
Allowed: SUCCESS, PARTIAL, EMPTY, PROCESSING, UNKNOWN, FAILED
data.usageobject | nulloptional
Usage value used by this API operation.
data.usage.billingStatusstring | nulloptional
Billing status value used by this API operation.
data.usage.chargedCreditsstring | integer | nulloptional
Charged credits value used by this API operation.
msgstring | nullrequired
Available upstream msg/errmsg/message is preferred for success and failure; Chinese is translated to English. Missing successful message is null. Platform-only errors and task states use platform English. Message text never determines success or retry.
timestringrequired
yyyy-MM-dd HH:mm:ss
traceIdstring | nullrequired
Trace id value used by this API operation.
tsstringrequired
Epoch milliseconds; global long serializer.

Accepted processing response

code 0 confirms acceptance. Use data.callId to query the same request; processing is not completion.

NameTypeRequiredDescription
codeintegerrequired
0 is a successful envelope; inspect data.status separately.
Constant: 0
coststringrequired
Elapsed processing milliseconds; not price. -1 for non-web context.
dataobjectrequired
Data value used by this API operation.
data.callIdstring | nullrequired
Call id value used by this API operation.
data.reasonstringrequired
Reason value used by this API operation.
Constant: IN_PROGRESS
data.retryablebooleanoptional
Retryable value used by this API operation.
data.statusstringrequired
Status value used by this API operation.
Constant: PROCESSING
data.taskIdstring | nulloptional
Task id value used by this API operation.
msgstring | nullrequired
Available upstream msg/errmsg/message is preferred for success and failure; Chinese is translated to English. Missing successful message is null. Platform-only errors and task states use platform English. Message text never determines success or retry.
timestringrequired
yyyy-MM-dd HH:mm:ss
traceIdstring | nullrequired
Trace id value used by this API operation.
tsstringrequired
Epoch milliseconds; global long serializer.

Error response

NameTypeRequiredDescription
codeintegerrequired
0 is a successful envelope; inspect data.status separately.
coststringrequired
Elapsed processing milliseconds; not price. -1 for non-web context.
dataobjectrequired
Data value used by this API operation.
data.callIdstring | nullrequired
Call id value used by this API operation.
data.reasonstring | nullrequired
Reason value used by this API operation.
data.retryablebooleanoptional
Retryable value used by this API operation.
data.statusstring | nullrequired
Status value used by this API operation.
data.taskIdstring | nulloptional
Task id value used by this API operation.
msgstring | nullrequired
Available upstream msg/errmsg/message is preferred for success and failure; Chinese is translated to English. Missing successful message is null. Platform-only errors and task states use platform English. Message text never determines success or retry.
timestringrequired
yyyy-MM-dd HH:mm:ss
traceIdstring | nullrequired
Trace id value used by this API operation.
tsstringrequired
Epoch milliseconds; global long serializer.

Response example

Example response envelope from the documented SEO API contract.

{
  "code": 0,
  "cost": "-1",
  "data": {
    "callId": "synthetic-call",
    "completedAt": null,
    "coverage": {
      "missing": [
        {
          "field": "synthetic",
          "reason": "UPSTREAM_FIELD_MISSING"
        }
      ],
      "status": "PARTIAL"
    },
    "requestedAt": "123",
    "result": {
      "items": [
        {
          "keyword": "synthetic",
          "keywordDifficulty": 9007199254740992,
          "missing": [
            {
              "field": "synthetic",
              "reason": "synthetic"
            }
          ],
          "relations": [
            {
              "depth": 1,
              "seed": "synthetic",
              "source": "synthetic"
            }
          ],
          "searchVolume": 9007199254740992
        }
      ],
      "language": "synthetic",
      "market": "synthetic",
      "requestedLimit": 1,
      "returnedCount": 1,
      "seed": "synthetic",
      "sources": [
        {
          "missingReason": "synthetic",
          "returnedCount": 1,
          "source": "synthetic",
          "status": "synthetic"
        }
      ]
    },
    "schemaVersion": "synthetic",
    "source": "synthetic",
    "status": "PARTIAL",
    "usage": {
      "billingStatus": "UNAPPROVED",
      "chargedCredits": "0"
    }
  },
  "msg": null,
  "time": "2026-01-01 00:00:00",
  "traceId": "synthetic-trace",
  "ts": "9007199254740993"
}

Retrieve a processing result

A response with PROCESSING and a callId means the result is still being prepared. Use the result query below with the returned identifier. This lookup reads the stored result and does not spend credits.

curl -X GET https://api.nexscope.ai/api/skill-api/v1/skills/seo-keyword-expand/calls/{callId} \
  -H "Authorization: Bearer nk-xxxxxxxxxxxxxxxxx"

Responses

CodeDescription
200HTTP request completed. Check JSON code; only 0 indicates business success or acceptance.
400Request JSON or required API parameters are invalid.
401API key is missing, invalid, or cannot be matched to a user.
5xxAPI execution or upstream service failed.

Data source, freshness, and limitations

Source, freshness, coverage, rate limits, and estimation notes are not specified in this API definition unless they appear in the request or response field documentation above. Do not assume official marketplace data or real-time freshness when it is not explicitly documented.

MCP

V2 recommended

Connect remote agents through the standard MCP 2025-11-25 Streamable HTTP endpoint. Use OAuth 2.1 Authorization Code with PKCE, or an API key for compatibility.

POST https://api.nexscope.ai/api/skill-api/v2/mcp
MCP-Protocol-Version: 2025-11-25
Content-Type: application/json
Authentication

OAuth clients request the mcp:tools scope. The endpoint's 401 response advertises protected-resource metadata for authorization discovery.

Call a tool

{
  "jsonrpc": "2.0",
  "id": "tool-call-1",
  "method": "tools/call",
  "params": {
    "name": "nexscope_seo_keyword_expand",
    "arguments": {
      "keyword": "nexscope",
      "language": "en",
      "limit": 10,
      "market": "US",
      "sources": [
        "suggestions",
        "related"
      ]
    }
  }
}
Legacy MCP v1

Existing API-key clients can continue using the compatibility endpoint. New integrations should use MCP v2.

GET / POST /api/skill-api/v1/mcp

Online test

Execute the current API with your API key and JSON payload.

Try it

Send a real request with the same contract shown in the reference.

Endpoint
/api/skill-api/v1/skills/seo-keyword-expand/run
Processing result endpoint
https://api.nexscope.ai/api/skill-api/v1/skills/seo-keyword-expand/calls/{resultId}
MCP method
nexscope_seo_keyword_expand
cURL
curl -X POST \
  https://api.nexscope.ai/api/skill-api/v1/skills/seo-keyword-expand/run \
  -H "Authorization: Bearer nk-..." \
  -H "Content-Type: application/json" \
  -d '{ "keyword": "nexscope", "language": "en", "limit": 10, "market": "US", "sources": [ "suggestions", "related" ] }'
Response
No response yet. Run the request to see the response here.
Processing result

Use the identifier returned by Run API. The tester selects the correct result query automatically, and result queries do not spend credits.

Result response
No task result yet. Query the task to see the generated output here.